4  Spatial distribution of priority fisheries and fishing effort

One of the most basic issues that is important for fisheries management is the understanding of the the distribution of key indicators and whether they change both in space and time. The common approach that is widely used in fisheries management is taking statistics at the receiving hand—landing sites. The central problem is that doing that only provide reference of the catch at the receiving hand—landing sites and ignore the source of fishery resource—fishing grounds. In this chapter we discuss catch rates, income and fishing effort at the collaborative fisheries managed areas (CFMA) and compare how they vary both in space and time.

The Kibiti, Mafia and Kilwa seascape (Figure 4.1) is a unique coastal areas because of myriad coastal habitats like magroves, seagrass and coral reefs, discharge of Rufiji River that form the largest estuary in the region, the change of speed and direction of trade winds that form monsoon winds, and the bathing of the East African Coastal Current that mix the water continuously.

Figure 4.1: The map of fisheries productive areas in Kibiti, Mafia and Kilwa Seascape

4.1 e-CAS

4.1.1 Fishery Data Available

The electronic catch assessment survey (e-CAS) system trial data collection begun in 2017 and until the end of 2020, recorded 5504 information of different marine fish species. Most of these information were recorded in the Kilwa district (3613), followed by Mafia (1629) and Kibit district has the lowest number of 262 in the e-CAS platform.

district Elasmobranch Octopus Others Prawn Reef Fish Small Pelagic Tuna Total
Kibiti 5 0 144 45 16 52 0 262
Kilwa 146 11 71 0 2701 624 60 3613
Mafia 61 355 192 0 720 206 95 1629
Total 212 366 407 45 3437 882 155 5504

The records in the e-CAS vary not only by the priority fishery but also for the collaborative fisheries managed areas (CFMAs). For instance, Figure 4.2 illustrated the reef fishery records constitute more than 62 percent and most of these records are from the Nyamanjisopoja CFMA. The small pelagic fishery constitute about 16 percent of the total records and like reef fish, most records are from Nyamanjisopoja CFMA (Figure 4.2). Other priority fishery are distributed across CFMAs at small proportions.

Figure 4.2: The percentage composition of priority fishery by CFMAs based on the avaialble e-CAS dataset

Though octopus and prawns are among important fisheries in the area, but their records in the e-CAS are few. For instance, we found that Octopus fishery is most recorded at BK CFMA and no single value of octopus has been recorded in CFMAS like Nyamanjisopoja (Figure 4.3), which has the highest records of Reef and small pelagic fishery. The absent of octopus fishery in other CFMA suggest that records in the e-CAS is fishery priority specific.

Figure 4.3: The percentage composition for octopus, small pelagic and reef fishery by CFMAs based on the avaialble e-CAS dataset

Figure 4.4: The percentage composition for octopus, small pelagic and reef fishery by CFMAs based on the avaialble e-CAS dataset

The fisheries governance framework in Kibiti, Mafia and Kilwa seascape is centred around the establishment of collaborative fisheries management areas (CFMAs). CFMAs are jointly managed by neighbouring BMUs who share fishing grounds. Among many key objectives of CFMA include conducting fishing pattern surveys and identifying priority fisheries. A functioning CFMA usually has BMU Statistics Committee capable to collect and analyse fisheries data for internal decision making. They are familiar with types and uses of fisheries data and guided through the process of designing and reviewing a data collection protocol.

Reporting of fisheries data in the electronic catch assessment system often depend on the collaboration with beach management unit (BMU). The willingness of BMU in a particular CFMA is key for successful data entry. We found that data entry into the e-CAS system relate closely to the BMU operations and data vary accordingly. For instance, more than 88 percent of data in Kibiti recorded fished at Mchimchunya CFMA (Figure 4.5). Similar to Kibiti, in Mafia the records in Mafia was dominated with fish from BK CFMA (Figure 4.6) and Nyamanjisopoja recorded a stagerring 85% of records in the e–CAS (@(Figure 4.7))

Figure 4.5: Collaborative fisheries man

Figure 4.6: Collaborative fisheries management areas in Mafia

Figure 4.7: Collaborative fisheries management areas in Kilwa

4.1.2 Catch Rates

Figure 4.8: The catch rates for octopus, small pelagic and reef fishery by CFMAs based on the avaialble e-CAS dataset

Figure 4.9: The spatial pattern of catch rates by CFMA for octopus, small pelagic and reef fishery by CFMAs based on the avaialble e-CAS dataset

4.1.3 Income

Figure 4.10: The income of fishers in octopus, small pelagic and reef fishery by CFMAs based on the avaialble e-CAS dataset

Figure 4.11: The spatial pattern of income of fishers in octopus, small pelagic and reef fishery by CFMAs based on the avaialble e-CAS dataset

4.1.4 Effort (Number of Active Fishers)

Figure 4.12: The fishing effort in octopus, small pelagic and reef fishery by CFMAs based on the avaialble e-CAS dataset

Figure 4.13: The fishing effort in octopus, small pelagic and reef fishery by CFMAs based on the avaialble e-CAS dataset

Figure 4.14: The spatial pattern of fishing effort in octopus, small pelagic and reef fishery by CFMAs based on the avaialble e-CAS dataset

4.2 MIMP

village Elasmobranch Octopus Others Reef Fish Small Pelagic Tuna NA_ Total
Banja 0 0 0 0 0 0 1 1
Bwejuu 1025 2083 108 7904 100 542 941 12703
Bweni 0 1 0 1 0 0 0 2
Chole 0 0 0 1 0 0 0 1
Chunguruma 127 165 5 673 32 76 383 1461
Dongo 326 64 79 2229 208 241 1219 4366
Juani 55 839 5 4474 123 348 757 6601
Kanga 4 2 0 864 61 12 144 1087
Kiegeani 46 1060 0 4302 68 324 1024 6824
Kifinge 0 0 0 1 0 0 0 1
Kilindoni 85 181 44 498 261 533 603 2205
Malimbani 0 1 0 0 0 0 0 1
Mbarakuni 0 4 0 3 3 0 0 10
Miburani 7 1525 4 1997 1514 15 124 5186
Utende 5 275 0 516 6 53 100 955
Total 1680 6200 245 23463 2376 2144 5296 41404

4.2.1 Availablle data

Figure 4.15: Priority fishery by priority group in MIMP

4.2.2 Selected Priority group

Figure 4.16: Selected priority fishery in Mafia

4.2.3 Catch Rates

Figure 4.17: Catch rates by CFMA in Mafia

Figure 4.18: Catch rates by CFMA in Mafia

Figure 4.19: Spatiall pattern of catch rate by priority fishery in CFMA in Mafia

4.2.4 Income

Figure 4.20: Fishers income by CFMA in Mafia

4.2.5 Effort (Number of Active Fishers)

Figure 4.21: Effort by CFMA in Mafia

Figure 4.22: Spatial distribution of fishing events in Mafia